Den 14.12.2017 21.25, skrev Daniel Vetter:
On Thu, Dec 14, 2017 at 08:10:06PM +0100, Noralf Trønnes wrote:
Add helper for initializing fbdev deferred I/O.
The cleanup could have happened in drm_fb_helper_fini(), but that would
have required me to set fb_info->fbdefio to NULL in a couple of drivers
before they call _fini() to avoid double defio cleanup. The problem is
that one of those is vboxvideo which lives in Greg's staging tree.
So I put the cleanup in drm_fb_helper_fbdev_teardown(), not perfect
but not that bad either.
Signed-off-by: Noralf Trønnes <nor...@tronnes.org>
---
drivers/gpu/drm/drm_fb_helper.c | 53 +++++++++++++++++++++++++++++++++++++++++
include/drm/drm_fb_helper.h | 6 +++++
2 files changed, 59 insertions(+)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 14aa83579e76..d5eeed1c7749 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -1022,6 +1022,48 @@ void drm_fb_helper_deferred_io(struct fb_info *info,
}
EXPORT_SYMBOL(drm_fb_helper_deferred_io);
+/**
+ * drm_fb_helper_defio_init - fbdev deferred I/O initialization
+ * @fb_helper: driver-allocated fbdev helper
+ *
+ * This function allocates &fb_deferred_io, sets callback to
+ * drm_fb_helper_deferred_io(), delay to 50ms and calls fb_deferred_io_init().
+ * drm_fb_helper_fbdev_teardown() cleans up deferred I/O.
+ *
+ * NOTE: A copy of &fb_ops is made and assigned to &info->fbops. This is done
+ * because fb_deferred_io_cleanup() clears &fbops->fb_mmap and would thereby
+ * affect other instances of that &fb_ops.
Do we need to call this before initial_config? Or after? Should be
documented imo.
Indeed it should be:
* This function allocates &fb_deferred_io, sets callback to
* drm_fb_helper_deferred_io(), delay to 50ms and calls
fb_deferred_io_init().
* It should be called from the &drm_fb_helper_funcs->fb_probe callback.
* drm_fb_helper_fbdev_teardown() cleans up deferred I/O.
Also, did you look into just fixing fb_deferred_io_cleanup to no longer do
this? Changing function tables is definitely not cool (because that means
we can't put them into read-only memory and protect them from attackers -
function tables are a high-value target in the kernel, since usually easy
to trigger them).
The fbdev operations isn't const:
struct fb_info {
struct fb_ops *fbops;
};
Fixing that is a project of it's own as a quick grep revealed:
drivers/video/fbdev/mb862xx/mb862xxfb_accel.c: info->fbops->fb_fillrect
= cfb_fillrect;
drivers/video/fbdev/mb862xx/mb862xxfb_accel.c: info->fbops->fb_copyarea
= cfb_copyarea;
drivers/video/fbdev/mb862xx/mb862xxfb_accel.c: info->fbops->fb_imageblit
= cfb_imageblit;
drivers/video/fbdev/mb862xx/mb862xxfb_accel.c: info->fbops->fb_fillrect
= mb86290fb_fillrect;
drivers/video/fbdev/mb862xx/mb862xxfb_accel.c: info->fbops->fb_copyarea
= mb86290fb_copyarea;
drivers/video/fbdev/mb862xx/mb862xxfb_accel.c: info->fbops->fb_imageblit
= mb86290fb_imageblit;
drivers/video/fbdev/uvesafb.c: info->fbops->fb_blank = NULL;
drivers/video/fbdev/uvesafb.c: info->fbops->fb_pan_display = NULL;
drivers/video/fbdev/aty/atyfb_base.c: info->fbops->fb_sync = atyfb_sync;
drivers/video/fbdev/aty/atyfb_base.c: info->fbops->fb_sync = NULL;
drivers/video/fbdev/aty/mach64_cursor.c: info->fbops->fb_cursor =
atyfb_cursor;
drivers/video/fbdev/core/fb_defio.c: info->fbops->fb_mmap =
fb_deferred_io_mmap;
drivers/video/fbdev/core/fb_defio.c: info->fbops->fb_mmap = NULL;
drivers/video/fbdev/vesafb.c: info->fbops->fb_pan_display = NULL;
drivers/video/fbdev/udlfb.c: info->fbops->fb_mmap =
dlfb_ops_mmap;
drivers/video/fbdev/smscufx.c: info->fbops->fb_mmap = ufx_ops_mmap;
drivers/video/fbdev/nvidia/nvidia.c: info->fbops->fb_imageblit =
nvidiafb_imageblit;
drivers/video/fbdev/nvidia/nvidia.c: info->fbops->fb_fillrect =
nvidiafb_fillrect;
drivers/video/fbdev/nvidia/nvidia.c: info->fbops->fb_copyarea =
nvidiafb_copyarea;
drivers/video/fbdev/nvidia/nvidia.c: info->fbops->fb_sync = nvidiafb_sync;
drivers/video/fbdev/nvidia/nvidia.c: info->fbops->fb_imageblit =
cfb_imageblit;
drivers/video/fbdev/nvidia/nvidia.c: info->fbops->fb_fillrect =
cfb_fillrect;
drivers/video/fbdev/nvidia/nvidia.c: info->fbops->fb_copyarea =
cfb_copyarea;
drivers/video/fbdev/nvidia/nvidia.c: info->fbops->fb_sync = NULL;
drivers/video/fbdev/nvidia/nvidia.c: info->fbops->fb_cursor = NULL;
drivers/gpu/drm/udl/udl_fb.c: info->fbops->fb_mmap = udl_fb_mmap;
drivers/gpu/drm/drm_fb_cma_helper.c: fbi->fbops->fb_mmap =
drm_fbdev_cma_deferred_io_mmap;
Noralf.
+ *
+ * Returns:
+ * 0 on success or a negative error code on failure.
+ */
+int drm_fb_helper_defio_init(struct drm_fb_helper *fb_helper)
+{
+ struct fb_info *info = fb_helper->fbdev;
+ struct fb_deferred_io *fbdefio;
+ struct fb_ops *fbops;
+
+ fbdefio = kzalloc(sizeof(*fbdefio), GFP_KERNEL);
+ fbops = kzalloc(sizeof(*fbops), GFP_KERNEL);
+ if (!fbdefio || !fbops) {
+ kfree(fbdefio);
+ kfree(fbops);
+ return -ENOMEM;
+ }
+
+ info->fbdefio = fbdefio;
+ fbdefio->delay = msecs_to_jiffies(50);
+ fbdefio->deferred_io = drm_fb_helper_deferred_io;
+
+ *fbops = *info->fbops;
+ info->fbops = fbops;
+
+ fb_deferred_io_init(info);
+
+ return 0;
+}
+EXPORT_SYMBOL(drm_fb_helper_defio_init);
+
/**
* drm_fb_helper_sys_read - wrapper around fb_sys_read
* @info: fb_info struct pointer
@@ -2743,6 +2785,9 @@ EXPORT_SYMBOL(drm_fb_helper_hotplug_event);
* The caller must to provide a &drm_fb_helper_funcs->fb_probe callback
* function.
*
+ * Drivers that need fbdev deferred I/O should use drm_fb_helper_defio_init()
+ * to set it up.
Not exactly sure why you put this here ... Maybe throw it into the
overview documentation, in a new paragraph that explains when you have a
non-NULL fb->dirty callback, then you most likely want to setup
defio_init. Except for the shmem fun. Explaining all that would be good
(maybe even put it under a "Framebuffer Flushing" heading).
Otherwise looks all reasonable to me.
Cheers, Daniel
+ *
* See also: drm_fb_helper_initial_config()
*
* Returns:
@@ -2818,6 +2863,7 @@ EXPORT_SYMBOL(drm_fb_helper_fbdev_setup);
void drm_fb_helper_fbdev_teardown(struct drm_device *dev)
{
struct drm_fb_helper *fb_helper = dev->fb_helper;
+ struct fb_ops *fbops = NULL;
if (!fb_helper)
return;
@@ -2826,7 +2872,14 @@ void drm_fb_helper_fbdev_teardown(struct drm_device *dev)
if (fb_helper->fbdev && fb_helper->fbdev->dev)
drm_fb_helper_unregister_fbi(fb_helper);
+ if (fb_helper->fbdev && fb_helper->fbdev->fbdefio) {
+ fb_deferred_io_cleanup(fb_helper->fbdev);
+ kfree(fb_helper->fbdev->fbdefio);
+ fbops = fb_helper->fbdev->fbops;
+ }
+
drm_fb_helper_fini(fb_helper);
+ kfree(fbops);
if (fb_helper->fb)
drm_framebuffer_remove(fb_helper->fb);
diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
index aa78ac3b8ad0..b069433e7fc1 100644
--- a/include/drm/drm_fb_helper.h
+++ b/include/drm/drm_fb_helper.h
@@ -276,6 +276,7 @@ void drm_fb_helper_unlink_fbi(struct drm_fb_helper
*fb_helper);
void drm_fb_helper_deferred_io(struct fb_info *info,
struct list_head *pagelist);
+int drm_fb_helper_defio_init(struct drm_fb_helper *fb_helper);
ssize_t drm_fb_helper_sys_read(struct fb_info *info, char __user *buf,
size_t count, loff_t *ppos);
@@ -423,6 +424,11 @@ static inline void drm_fb_helper_deferred_io(struct
fb_info *info,
{
}
+static inline int drm_fb_helper_defio_init(struct drm_fb_helper *fb_helper)
+{
+ return -ENODEV;
+}
+
static inline ssize_t drm_fb_helper_sys_read(struct fb_info *info,
char __user *buf, size_t count,
loff_t *ppos)
--
2.14.2
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